Hi the client will probably dictate how may times per week they want, so don’t get to hung up about the side.
You can ask how long it currently takes to clean if you are unsure, although imho the client is usually the worst person to answer this as they have no idea.
it also depends on the level of detail they require on how long it takes, this is tricky again as clients will say they want this, that and the other but pretty much choose the cheapest quote.
If by any chance you are speaking with someone who can make decision ask them what they specifically want, what they are looking to pay and see if you think it is feasible and try to get it sewn up there and then, usually though whoever shows you around has been assigned the job and doesn’t know/care about this, so you'll have to then take a chance and work it out.
It is a learning experience, you will get better if you do enough.
Good luck.